F. J. Hassler disclosed in U.S. Pat. No. 3,110,326 a method and barn structure for bulk curing and drying whole leaf flue-cured tobacco. Prior to Hassler's bulk curing system, the "stick barn" represented the state of the art of curing and drying flue-cured tobacco. Generally, in the old stick barn system the tobacco leaves were looped onto opposite sides of an elongated stick in small bundles (usually 2 to 3 leaves per bundle) with the bundles being disposed in spaced apart relationship. Hassler discovered that tobacco leaves could be racked and cured and dried in bulk form by peripherally confining an assembled volume of aligned leaves about the stalk or butt end of the leaves making up the bulk volume, as illustrated in FIGS. 3 and 7 of U.S. Pat. No. 3,110,326. The rack illustrated is known as a conventional bulk tobacco rack and is particularly characterized in that it is a single tier rack, i.e., the volume of bulk leaves supported has a depth (or height) of one leaf length when disposed within the curing and drying structure.
Typically in loading a rack of the type disclosed in the Hassler patent, harvested tobacco leaves are transported from the field in a trailer or other suitable transport device and the leaves are transferred manually therefrom to a bin or form supporting a base portion of the single tier rack. The bin or form enables the tobacco leaves to be neatly aligned with the stalk or butt ends of the leaves lying in substantially the same plane. Once a selected volume of leaves have been manually aligned within the bin or form, a series of tines are inserted through the bulk volume of tobacco leaves and the frame carrying the tines is fastened to the base portion thereof. There-after the rack is removed from the bin or form and placed within a curing and drying structure where the walls thereof directly support parallel tier rails which in turn support the rack at any one of several tier levels.
Basically commercial bulk curing systems of today remain fundamentally unchanged over the basic Hassler design, and have over the past years been used for the most part to cure and dry manually harvested tobacco. But in the last several years, automatic tobacco harvesters (of the type shown in U.S. Pat. No. 3,507,103) have begun to meet with substantial commercial success and many farmers are now using such automatic harvesters which have the capacity to harvest 4000 to 8000 lbs of tobacco per hour. This range of capacity is significantly greater than that typically found in manual harvesting operations. With the present system of bulk handling it is diffucult, if at all possible in certain situations, to transfer the tobacco automatically harvested into the curing and drying system as fast as it is harvested. Where the harvested tobacco cannot be transported and properly placed within curing and drying structures at a rate comparable to the harvesting rate, one is likely to find that this idles the harvester at times and may even seriously decrease the total harvesting capacity of the harvester which may be critical in certain farm operations.
Moreover, the scarcity of farm labor has been a major factor in tobacco farmers converting to bulk curing and drying systems and to the use of fully automatic harvesters. While such automatic tobacco harvesters and bulk curing and drying systems have substantially reduced the total labor force required to harvest a given quantity of tobacco, there still remains a significant labor requirement in handling the harvested tobacco between the field harvesting and curing and drying operations, particularly in view of the fact that the leaves are manually handled and retransferred. Thus, the manual handling of the leaves at some stage of leaf handling between field harvesting and curing and drying still requires a significant amount of farm labor relative to the availability of farm labor today. In addition, the manual handling and retransfer of leaves does result in leaf damage--and consequently adversely affects, to at least some degree, the final quality of the tobacco.